This paper proposes a compact polarization microstrip antenna based on double-layer structure. The band- width of the whole antenna is widened by expanding the top and bottom layers respectively. After the design of a...This paper proposes a compact polarization microstrip antenna based on double-layer structure. The band- width of the whole antenna is widened by expanding the top and bottom layers respectively. After the design of antenna structure and adjustment of size, the proposed antenna can achieve both the left- and right-hand circular polariza- tions in 2.33 GHz--2.97 GHz. Measurement results indicate that the effective bandwidth is 640 MHz in S-band and the relative bandwidth can achieve 24% with S, less than- 15 dB.展开更多
In this work, the aerodynamic stability of the Yichang Suspension Bridge over Yangtze River during erection was determined by three dimensional nonlinear flutter analysis, in which the nonlinearities of structural dy...In this work, the aerodynamic stability of the Yichang Suspension Bridge over Yangtze River during erection was determined by three dimensional nonlinear flutter analysis, in which the nonlinearities of structural dynamic characteristics and aeroelastic forces caused by large deformation are fully considered. An interesting result obtained was that the bridge was more stable when the stiffening girders were erected in a non symmetrical manner as opposed to the traditional symmetrical erection schedule. It was also found that the severe decrease in the aerodynamic stability was due to the nonlinear effects. Therefore, the nonlinear factors should be considered accurately in aerodynamic stability analysis of long span suspension bridges during erection.展开更多
The design and optimization of a self-complementary two-arm Archimedean spiral antenna backed by an absorptive cavity were presented. Parametric studies on the proposed antenna structure were carried out by using CST ...The design and optimization of a self-complementary two-arm Archimedean spiral antenna backed by an absorptive cavity were presented. Parametric studies on the proposed antenna structure were carried out by using CST MWS. Simulation results show that the proper choice of spiral turns and cavity depth can miniaturize the dimensions of the cavity-backed spiral antenna presented here. According to simulation results, prototype antennas operating in the 6 12 GHz band are fabricated and the dimension of the proposed cavity-backed spiral antenna is 22 mm (diameter)×15 mm (height). The performance of the proposed antenna was measured and compared with the simulation results. It is shown that the experimental results are consistent with the theoretical predictions and the suggested antenna is good enough to adapt for various wideband applications.展开更多
A compact multiband patch antenna is designed by using HFSS in this work, which is filled with composite right/left-handed transmission line （CRLH-TL） structures. The simulated results reveal that the operating freq...A compact multiband patch antenna is designed by using HFSS in this work, which is filled with composite right/left-handed transmission line （CRLH-TL） structures. The simulated results reveal that the operating frequency becomes lower with left-handed （LH） characteristics of the CRLH-TL structures enhanced, which enable antenna physical size reduction to a large extent. The proposed antenna is fabricated on the substrate Rogers R03201 （relative permittivity of 10.2）, which has a compact size of 12 mm×12 mm × 4 mm. Moreover, this antenna exhibits monopole-like radiation pattern at one resonance frequency and patch-like radiation at the other four resonant frequencies. Therefore, the designed antenna is useful for communication systems.展开更多
A five-band metamaterial absorber(MMA) based on a simple planar structure is proposed.It utilizes different areas of a single unit cell to match impedance,and produces different absorptive frequencies.Numerical calcul...A five-band metamaterial absorber(MMA) based on a simple planar structure is proposed.It utilizes different areas of a single unit cell to match impedance,and produces different absorptive frequencies.Numerical calculation shows that the MMA has five different absorption peaks at 3.78 GHz,7.66 GHz,10.9 GHz,14.5 GHz and 16.7 GHz,and their absorption rates reach 95.5%,98.6%,95.7%,96.6%and 99.8%,respectively.The proposed structure is polarization insensitive for transverse electric(TE) and transverse magnetic(TM) incident waves.Also,the absorptive characteristics over large incident angles are examined.In addition,we analyze the absorption mechanism by the surface current density and power flow density distributions.This simple structure provides a way to design multi-band MMA,and also saves the cost of fabrication.展开更多
基金Supported by National Basic Research Program of China ("973" Program,No.2007CB310605)
文摘This paper proposes a compact polarization microstrip antenna based on double-layer structure. The band- width of the whole antenna is widened by expanding the top and bottom layers respectively. After the design of antenna structure and adjustment of size, the proposed antenna can achieve both the left- and right-hand circular polariza- tions in 2.33 GHz--2.97 GHz. Measurement results indicate that the effective bandwidth is 640 MHz in S-band and the relative bandwidth can achieve 24% with S, less than- 15 dB.
文摘In this work, the aerodynamic stability of the Yichang Suspension Bridge over Yangtze River during erection was determined by three dimensional nonlinear flutter analysis, in which the nonlinearities of structural dynamic characteristics and aeroelastic forces caused by large deformation are fully considered. An interesting result obtained was that the bridge was more stable when the stiffening girders were erected in a non symmetrical manner as opposed to the traditional symmetrical erection schedule. It was also found that the severe decrease in the aerodynamic stability was due to the nonlinear effects. Therefore, the nonlinear factors should be considered accurately in aerodynamic stability analysis of long span suspension bridges during erection.
文摘The design and optimization of a self-complementary two-arm Archimedean spiral antenna backed by an absorptive cavity were presented. Parametric studies on the proposed antenna structure were carried out by using CST MWS. Simulation results show that the proper choice of spiral turns and cavity depth can miniaturize the dimensions of the cavity-backed spiral antenna presented here. According to simulation results, prototype antennas operating in the 6 12 GHz band are fabricated and the dimension of the proposed cavity-backed spiral antenna is 22 mm (diameter)×15 mm (height). The performance of the proposed antenna was measured and compared with the simulation results. It is shown that the experimental results are consistent with the theoretical predictions and the suggested antenna is good enough to adapt for various wideband applications.
文摘A compact multiband patch antenna is designed by using HFSS in this work, which is filled with composite right/left-handed transmission line （CRLH-TL） structures. The simulated results reveal that the operating frequency becomes lower with left-handed （LH） characteristics of the CRLH-TL structures enhanced, which enable antenna physical size reduction to a large extent. The proposed antenna is fabricated on the substrate Rogers R03201 （relative permittivity of 10.2）, which has a compact size of 12 mm×12 mm × 4 mm. Moreover, this antenna exhibits monopole-like radiation pattern at one resonance frequency and patch-like radiation at the other four resonant frequencies. Therefore, the designed antenna is useful for communication systems.
基金supported by the National Natural Science Foundation of China(No.61475079)the Ningbo Optoelectronic Materials and Devices Creative Team(No.2009B21007)+3 种基金the Educational Committee of Zhejiang Province(No.Y201430863)the Ningbo Natural Science Foundation(No.2014A610144)the Scientific Research Foundation of Graduate School of Ningbo University(No.G15056)the K.C.Wong Magna Fund in Ningbo University
文摘A five-band metamaterial absorber(MMA) based on a simple planar structure is proposed.It utilizes different areas of a single unit cell to match impedance,and produces different absorptive frequencies.Numerical calculation shows that the MMA has five different absorption peaks at 3.78 GHz,7.66 GHz,10.9 GHz,14.5 GHz and 16.7 GHz,and their absorption rates reach 95.5%,98.6%,95.7%,96.6%and 99.8%,respectively.The proposed structure is polarization insensitive for transverse electric(TE) and transverse magnetic(TM) incident waves.Also,the absorptive characteristics over large incident angles are examined.In addition,we analyze the absorption mechanism by the surface current density and power flow density distributions.This simple structure provides a way to design multi-band MMA,and also saves the cost of fabrication.
